The present invention relates generally to three phase power converters used in high power motor drive systems. The invention relates more specifically to a fast response five level power inverter circuit capable of medium voltage operation without series connection of power electronic switching devices and to an associated modulation control for determining gate timings for the power electronic switching devices.
Baker et al., U.S. Pat. No. 4,270,163, and others have proposed generalized inverter power circuits having four or more levels. This proposed multi-level converter configuration, when used in a five level embodiment, has multiple practical issues impeding construction of a converter system including: twice the direct current (DC) bus voltage of this invention, difficulties obtaining practical high speed clamp diodes (clamp diodes require higher blocking voltages than the switching devices), complicated capacitor balancing requirements, and long convoluted inductive circuit commutation paths.